The present invention relates to a method of reducing or scavenging hydrogen sulfide associated with or in a hydrocarbon stock. More particularly, the present invention relates to a method of reducing or scavenging hydrogen sulfide in a liquid hydrocarbon stock and/or gaseous hydrocarbon stock in admixture with hydrogen sulfide gas.
In the drilling, production, transport, storage, and processing of crude oil, including waste water associated with crude oil production, and in the storage of residual fuel oil, hydrogen sulfide which is a very toxic substance is often encountered. Also, at the oil well head, hydrogen sulfide-containing light hydrocarbon vapors are emitted and must be controlled. Uncontrolled emission of hydrogen sulfide gives rise to severe health hazards. Burning of such vapors neither solves the toxic gas problem nor is economical since the light hydrocarbons have significant value. Furthermore, hydrogen sulfide is often present in the underground water removed with the crude oil, in the crude oil itself and in the gases associated with such water and oil. When the water and oil are separated one from the other by the use of separation tanks, demulsification apparatus and the like, intolerable amounts of hydrogen sulfide are emitted as a gas which is associated with water and hydrocarbon vapors. Natural gases are often sour; that is they contain some hydrogen sulfides.
In accordance with the present invention, crude oil production fluids containing hydrogen sulfide, as well as hydrocarbon gases, such as natural gas or off gas production fluids from the production, transport, storage, and refining of crude oil can be controlled in a convenient and economical manner.
The Prior Art
The use of various aldehydes which react with hydrogen sulfide has been known in the prior art for sometime. For example, U.S. Pat. No. 2,426,318 discloses a method of inhibiting the corrosive action of natural gas and oil containing soluble sulfides on metals by utilizing certain aldehydes, preferably formaldehyde.
U.S. Pat. No. 4,680,127 suggests using glyoxal to reduce the amount of hydrogen sulfide in hydrogen sulfide-containing dry gaseous and wet gaseous media.
U.S. Pat. No. 4,515,759 discloses a process for removal of hydrogen sulfide from gas mixtures, particularly gas mixtures containing hydrocarbons, wherein the gas mixture is treated with a buffered aqueous solution of a water soluble nitrite, such as sodium nitrite.
There is a need in the liquid fuel industry for treating a liquid hydrocarbon stock and a wet or dry gas mixture containing hydrogen sulfide and a low boiling or light hydrocarbon with a highly effective chemical agent that is both water and hydrocarbon soluble. Thus, when the gaseous mixture is wet, the agent will scavenge the hydrogen sulfide from both the aqueous vapors and the hydrocarbon vapors.